home made risers with "activate 1x" hotplug bridge, and additional power molex

what is "activate 1x" hotplug bridge?
and is there anywhere a technical sketch how to add an additional power molex (because for me one card has broken without additional power molex)
TIA
i would like some 1x > 1x risers with the PCI-E presence mod please. I don't need the molex mod. i can provide risers.